Name: Armillaria tabescens (Scop.) Emel
Most Confident Observations:
Copyright © 2011 Stephen (Ιερονυμοσ)
Copyright © 2017 John (John FungiFlora)
Copyright © 2018 walt sturgeon (Mycowalt)
Version: 15
Previous Version 

First person to use this name on MO: Nathan Wilson
Editors: Alan Rockefeller, Erlon, Jacob Kalichman


Domain: Eukarya

Kingdom: Fungi

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Agaricales

Family: Physalacriaceae

Genus: Armillaria

Brief Description:

Cap: 1-6 cm across at maturity; convex at first, becoming broadly convex or flat in age; dry; tan to tawny brown or cinnamon brown—or sometimes yellow to yellowish; when young covered with darker brown scales, but at maturity the scales are often concentrated near the center and vaguely radially arranged; the margin often becoming slightly lined.

Gills: Running down the stem or nearly so; close or nearly distant; whitish with pinkish hints; sometimes bruising or discoloring slightly pinkish to brownish.

Stem: 5-20 cm long; 0.5-1.5 cm. thick; tapering to base; bald and pale near apex, darker and nearly hairy below; without a ring.

Flesh: Whitish to watery tan; sometimes insubstantial in stem.

Odor and Taste: Taste mild or bitter; odor sweet.

Chemical Reactions: KOH negative on cap surface.

Spore Print: White.

Microscopic Features: Spores 8-10 × 5-7 µ; smooth; more or less ellipsoid; inamyloid; with a prominent apiculus. Pileipellis a cutis of brown, frequently septate elements 7.5-15 µ wide, occasionally arranged in upright fascicles. Cheilocystidia clavate to subclavate or subsaccate; to about 40 × 10 µ; thin-walled; hyaline. Pleurocystidia absent. Basidia 2- and 4-sterigmate; not basally clamped.

Descriptions: [Create]


Add Comment
By: Erlon (Herbert Baker)
2018-08-24 23:41:46 CDT (-0400)

The move to Desarmillaria was based on the phylogenetic analyses of six genetic loci.

“Of late, the translation elongation factor-1 alpha (tef1) region has successfully been used to distinguish Armillaria species that ITS or IGS could not separate (Antonín et al., 2009; Brazee et al., 2011; Coetzee, Wingfield, Zhao, van Coller, & Wingfield, 2015; Elías-Román et al., 2013; Guo et al., 2016; Hasegawa et al., 2010; Klopfenstein et al., 2017; Maphosa, Wingfield, Coetzee, Mwenje, & Wingfield, 2006; Mulholland et al., 2012; Ota, Kim, Neda, Klopfenstein, & Hasegawa, 2011; Ross-Davis, Hanna, Kim, & Klopfenstein, 2012; Tsykun et al., 2013).
On the basis of a recent multilocus phylogenetic study that included tef1, the taxonomy of some Armillaria species was revised in species that lack an annulus on the stipe. As a result, A. ectypa and A. tabescens were assigned to the newly described genus, Desarmillaria (Koch et al.,2017)…Consistent with previous phylogenetic studies, the tef1 analysis had better resolution than the ITS analysis. These distribution data of Armillaria and Desarmillaria species will contribute to better management of Armillaria root disease…” (Park et. al, 2018)

Park, Ki Hyeong, et al. (2018) “Re‐evaluation of Armillaria and Desarmillaria in South Korea based on ITS/tef1 sequences and morphological characteristics.” Forest Pathology: e12447.

Lee, Dong-Hyeon, et al. (2018) “First Report of Desarmillaria tabescens found on Ulmus pumila in South Korea.” Plant Disease (2018): PDIS-01.

By: Alan Rockefeller (Alan Rockefeller)
2018-08-24 21:39:32 CDT (-0400)

Unnecessary splits should be ignored.

MyCoPortal has a great solution
By: Oluna & Adolf Ceska (
2018-02-01 19:37:58 CST (-0500)

For their searches, MyCoPortal has a great solution. It is the Taxonomic Thesaurus that gives you search results not only for the name you entered, but also for the synonyms of the name you searched for. MO should make a deal with MyCoPortal and build the Taxonomic Thesaurus into our MO system. I can imagine that to build up such Thesaurus and beef it up with names requires unique encyclopedic knowledge of the nomenclature of fungi. Would it be possible to get it from the MyCoPortal as a sealed unit and let it on them to make the updates?

By: Jacob Kalichman (Pulk)
2018-02-01 19:31:48 CST (-0500)

Requiring everyone to agree that a name shouldn’t be used is far too strict. There are always going to be idiots clinging to patently wrong old names for terrible reasons.

The reasons for Armillaria tabescens are good, but the reasons for Desarmillaria tabescens are better, and letting multiple names float around is confusing. From my post on FB: “That’s how the genera are going to be treated in future literature. When you read a new paper next year you don’t want to have to figure out if the cool weird attribute it’s describing is about the hobby Armillaria or the mycologists’ Armillaria. And when some new Desarmillaria species is described without a corresponding Armillaria combination, you’re going to have to accept the genus anyway.” I’m sympathetic to questionable cases having multiple names accepted (Lepista nuda and Clitocybe nuda), but I’m not convinced there’s that much ambiguity here.

Anyway, there are much more egregious errors in other parts of MO so this is the last time I’ll deprecate “A. tabescens” (…for now…)

By: Alan Rockefeller (Alan Rockefeller)
2018-02-01 19:09:21 CST (-0500)

There is nothing wrong with this name so it should not be deprecated. Only names that everyone agrees should not be used should be deprecated. There are lots of examples of taxa with multiple valid names, and which one to use is a matter of personal preference and taxonomic philosophy.

Gentlemen, Stop it!
By: Oluna & Adolf Ceska (
2018-02-01 18:49:19 CST (-0500)

This honey mushroom does not really care, how it is called. Follow the Interantional Code of Nomenclature of … and forget deprecation!

By: Jacob Kalichman (Pulk)
2018-02-01 17:14:40 CST (-0500)

It wasn’t a mistake; they used it multiple times, obviously consciously. It’s not a fluke; these are different authors, a year later from the 2017 paper that established it as a genus.

By: Alan Rockefeller (Alan Rockefeller)
2018-02-01 16:52:50 CST (-0500)

Just because the new Armillaria paper made the mistake of using Desarmillaria doesn’t mean that we need to make the same error on MO.

By: Jacob Kalichman (Pulk)
2018-02-01 15:55:32 CST (-0500)

Agreed, but the split was made and other Armillariologists have adopted the name. Because one synonym should be chosen as preferred and this is the direction taxonomists have chosen, MO should use Desarmillaria. I would love to see a publication explicitly rejecting Desarmillaria, and therefore reason to change it back on MO.

By: Alan Rockefeller (Alan Rockefeller)
2018-02-01 14:36:02 CST (-0500)

Desarmillaria was an unnecessary split.

Deprecate the deprecation! Consensus is nonsensus
By: Oluna & Adolf Ceska (
2018-02-01 12:34:36 CST (-0500)
By: Jacob Kalichman (Pulk)
2018-02-01 10:11:17 CST (-0500)

A new Armillaria paper with entirely different authors uses the name without qualification; this makes it the current Armillariologist “consensus”.

By: Erlon (Herbert Baker)
2017-07-11 20:48:08 CDT (-0400)

“Species of Guyanagaster and Desarmillaria represent extant taxa of these early diverging lineages. Desarmillaria represents an armillarioid lineage that was likely much more widespread in the past. Guyanagaster likely evolved from a gilled mushroom ancestor and could represent a highly specialized endemic in the Guiana Shield. Armillaria species represent those that evolved after the shift in climate from warm and tropical to cool and arid during the late Eocene. No species in either Desarmillaria or Guyanagaster are known to produce melanized rhizomorphs in nature, whereas almost all Armillaria species are known to produce them. The production of rhizomorphs is an adaptation to harsh environments, and could be a driver of diversification in Armillaria by conferring a competitive advantage to the species that produce them.” (Koch et al., 2017)

By: Alan Rockefeller (Alan Rockefeller)
2017-07-11 19:36:31 CDT (-0400)

There was no good reason to split Armillaria.

By: Erlon (Herbert Baker)
2017-03-14 10:45:52 CDT (-0400)
A. tabescens or A. socialis?
By: Dmitriy Bochkov (convallaria)
2012-08-01 02:07:24 CDT (-0400)

There is a paper, External Link , which concludes that the correct name for this species is Armillaria socialis (in my opinion, reasonably). But Mycobank and Spec.fungorum give these two as different species (last year they called the A. tabescens the correct name, I guess that is where the synonymy here came from). Should we make A. socialis the correct name (possibly leaving tabescens as valid too)?

Created: 2007-06-19 01:53:42 CDT (-0400) by Nathan Wilson (nathan)
Last modified: 2018-08-24 23:41:47 CDT (-0400) by Alan Rockefeller (Alan Rockefeller)
Viewed: 3523 times, last viewed: 2019-02-17 18:24:43 CST (-0500)
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